Malaria vector studies in Maputo, Mozambique - implications for control

Objectives. The objectives of this study were to obtain data on vector species composition, their feeding preferences and useful genetic markers. Methodology. Mosquitoes were collected both from indoors and outdoors in seven localities (two of which were under insecticide house spraying) around Maputo, Mozambique, between March and May 1994. Members of the Anopheles gambiae group of species were identified by the polymerase chain reaction (PCR), chromosomal methods or both. Blood meals from blood-fed mosquitoes were identified to determine their source. Leg banding measurements of these mosquitoes were also done. Results and conclusions. Two species of the An. gambiae group, namely An. arabiensis and An. merus, were identified from indoor and outdoor-collected samples. An. funestus and Culex quinquefasciatus were also collected. Two inversions, 2Rb and 3Ra, were reported in An. arabiensis, a pattern commonly seen in populations of this species from both eastern and southern Africa. There was, however, no chromosomal polymorphism in An. merus, a species being documented in Maputo for the first time. The blood meals analysed for An. arabiensis and An. merus showed that they had fed on humans, an indication that the two species could be playing an important role in the transmission of malaria in the area. The An. arabiensis population from Maputo is characterised by a peak frequency of 0.07 mm, typical of a population from an unsprayed area. This study has therefore provided useful data in monitoring future malaria vector control interventions using house spraying.